The use of fuses and anti-fuses (or antifuses) in integrated circuits has become widespread in recent years. And integrated circuits (ICs) often require selectively permanently programmable electrical connections between circuit nodes. Such a connection can be implemented by an anti-fuse link (anti-fuse). An anti-fuse is a structure alterable to a conductive state, or in other words, an electronic device that changes state from not conducting to conducting. Equivalently, the binary states can be either one of high resistance and low resistance in response to electric stress, such as a programming voltage or current.
A conventional anti-fuse structure is fabricated with structure similar to that of a capacitor: two electrical terminals are separated by a dielectric layer. In order to connect the two electrical terminals (in other words, to program an anti-fuse structure), a programming voltage is applied across the anti-fuse terminals for breaking down the interposed dielectric layer and forming a conductive link between the anti-fuse terminals. However, the programming voltage depends only on a thickness of the dielectric layer that makes it difficult to design different programming voltages on one wafer/chip.
Accordingly, there is a need in the art for a process to achieve higher design flexibility of anti-fuse structures.